Question

if triangle ABC is similar to the triangle QRP, ar(ABC)/ar(PQR)= 9/4, AB=18 cm BC=15 cm, then PR= ?

Answer 1

Heya your answer is

Given :

Area of ∆ ABCArea of ∆QRP = 94


AB = 18 cm , BC = 15 cm So PR = ?

We know when two triangles are similar then " The areas of two similar triangles are proportional to the squares of their corresponding sides.

Area of ∆ ABCArea of ∆ QRP = AB2QR2 = BC2PR2 = AC2QP2
So , we take
Area of ∆ ABCArea of ∆ QRP = BC2PR2

Now substitute all given values and get

94 = 152PR2

Taking square root on both hand side , we get

32 = 15PR

PR = 10 cm

Answer 2

ar(ABC)/ar(PQR)=K²

K IS CONSTANT

K=3/2

SINCE TRIANGLES ARE SIMILAR

BC/PR=K

PR=BC/K
PR=15x2/3

PR=10